1. Field of the Invention
The present invention relates to a process for producing a styrene-based polymer, and more particularly, it relates to a process for an efficient production of a styrene-based polymer having a stereostructure in which the chains of polymers are in a high syndiotactic configuration.
2. Description of the Related Arts
Styrene-based polymers having a stereostructure which is in atactic or isotactic configuration have heretofore been well known, but recently styrene-based polymers having a stereostructure of a high syndiotactic configuration have been developed, one of which is disclosed in Japanese Patent Application Laid-Open No. 187708/1987.
The reaction system, in which styrene-based polymers having syndiotactic configuration are under production, solidifies when the polymerization reaction proceeds to a conversion of approximately 20%, while the reaction continues further until a higher conversion is accomplished. By applying an appropriate shearing force at said solidification stage, polymers in a favorable powder form can be obtained. If the reaction rate at an early stage is too high, however, a large shearing force is required for inhibiting the formation of macro-particles, which is involved in a fear that the inside of the reactor might be wholly covered with solid polymers. There is also a fear of causing a melt-fusion of polymers, since it is difficult to control the reaction heat caused by reaction at a high rate.
On the contrary, if the reaction rate is lowered, for the purpose of inhibiting the formation of macro-particles, it takes much time to complete the polymerization and the production efficiency is lowered.